God forbid - Phrases/Idioms
Also, heaven forbid. May God prevent something from happening or being the case. For example, God forbid that they actually encounter a bear, or Heaven forbid that the tornado pulls off the roof. This term, in which heaven also stands for “God,” does not necessarily imply a belief in God's direct intervention but merely expresses a strong wish. [c. 1225] For a synonym, see perish the thought.